1. Field of the Invention
The present invention relates to a heat dissipating structure which prevents airflow from flowing back, and more particularly, to a heat dissipating structure utilizing a resilient component to drive a shutter to close an opening so as to prevent airflow from flowing back.
2. Description of the Prior Art
Consumer electronic products have more and more functions with progress of technology. Hence the demand for performance increases accordingly. The high performance brings high energy consumption resulting in resonance, noise, thermal problems, and so on. For example, the reliability and stability of electronic products reduce if heat generated by internal electronic components can not be dissipated effectively. The conventional solution of thermal problem is utilizing a heat dissipating system, such as a fan, a heat sink, a heat pipe, or a cooling chip for reducing temperature of the electronic components so that the electronic products can operate normally.
For instance, in order to dissipate heat generated by electronic components disposed inside a computer system in an air-cool manner effectively, a plurality of fans is utilized to exhaust cold air from surroundings into a main board disposed inside the computer system, so as to cool the electronic components disposed on the main board. However, when a fan stops by being shut down or being broken, airflow driven by the other fans flows back to the surroundings through an opening of the fan due to pressure difference, so that the cooling efficiency of the fan is decreased. In order to solve the above-mentioned drawback, a conventional backflow-prevention mechanism prevents the corresponding opening when the fan is shut down for preventing the airflow driven by the other fans from flowing back to the surroundings through the opening of the fan due to the pressure difference. The conventional backflow-prevention mechanism often includes a shutter pivoted to a shaft, and the shutter covers the opening by its gravity. That is to say, the airflow driven by the fan moves the shutter away from the opening when the fan works. When the fan stops, the gravity of the shutter drives the shutter to cover the opening naturally. It should be mentioned that when the airflow driven by the fan pushes the shutter, a specific angle between the shutter and the opening is kept due to force equilibrium of the gravity of the shutter and the airflow. Therefore, part of the opening is covered and the airflow passing through the opening is decreased, so that the cooling efficiency of the fan is decreased. The angle between the shutter and the opening in the force equilibrium can be adjusted according to the power of the fan and material of the shutter, which results in design limitation. For example, the fan with low power is unsuitable to the shutter having heavy weight, but the shutter with slight weight does not have enough structural strength. Thus, design of a heat dissipating structure capable of preventing the airflow from flowing back is an important issue in the thermal design.